Hi.I want to transfer my Wii data to my wii U but my Wii asks for update(it’s 4.3U).It has been hacked to play Isos,a friend of mine did it and he doesn't remember what he did.I need help.I do not know how to use ANYTHING of wiihacking.I want to transfer data from my wii to the wii U and plays isos on my wii.You were convincing on a post you wrote about the subject,so maybe you could guide me through?Please!!!!

In other words: you'll need either to let it update (and overwrite 249 with that stub...don't worry: you should be able to rehack your wii afterwards), or install a cIOS with a higher version number than that.
I haven't checked modmii lately, but I guess it allows you to download a decent cIOS for that slot, along with a number that's higher than that.

You can find modmii in the stickies in the hacking section of the wii. It gives plenty of info on what it does, making it easy for beginners. For further info, I can advice these sites:
-https://sites.google.com/site/completesg/ (for what goes on under the hood of the wii)
-http://www.wiibrew.org/wiki/Main_Page (for specific questions)